When to Worry About a Child's Fever

Nearly every parent has felt their child’s hot, feverish forehead and gotten worried. Is it serious? How high is too high? Should my child go to the doctor?

Many doctors see concerned parents bring in their feverish children for treatment. When it comes to fever, prompt medical treatment can be very important. However, in most cases, fevers aren’t dangerous and can even be viewed as helpful as they fight infections naturally.

Consider these questions when your child has a fever:

1. What’s causing the fever?
2. What’s the correct way of taking your child’s temperature?
3. When should you use fever reducers?
4. When should you take your child to the doctor?

Causes of Fever in Children

Viruses are the most common cause of infection in kids. The second most common source of infection is bacteria. Both types of infections can cause fevers.

Fever is a healthy sign the body is working properly to fight and overcome an infection. Through a chemical reaction, your body elevates your core temperature to stop bad viruses and bacteria from replicating. Since viruses and bacteria can normally only reproduce when conditions are just right, this is a very effective way to shut them down.

However, in very young children — especially infants under three months old — fevers can be concerning. This is because their immune systems are still developing, and a fever can put them at risk for a severe infection.

For preschoolers and school-age children, pediatricians worry less about fevers unless they last for four or more days. Look out for the following symptoms:

• Significant listlessness and irritability.
• Bad sore throat.
• Worsening cough.
• Pain with urination.

The Right Way to Take Your Child's Temperature

Knowing how to take your child’s temperature correctly is one of the most important parenting skills. There are different methods, depending on your child’s age.

• Newborn to 3 months – A regular digital thermometer is recommended to take temperature rectally. Tympanic (ear) thermometers aren’t recommended as infants in this age group tend to have smaller and wetter ear canals that may lead to incorrect readings.
• 3 months to 4 years – Rectal temperature is still the most accurate for this age group, but at this age you can also take temperatures in the armpit. This is also a good age to start using a temporal artery thermometer on the forehead. With a digital ear thermometer, wait until your child is at least 6 months old.
• 4 years and above – A digital thermometer held under the tongue is ideal as children of this age should be able to hold it steadily enough for an accurate reading.

Learn more about our thermometer guidelines, including detailed instructions on how to take your child’s temperature.

When to Use Fever Reducers in Children

Fever-reducing medicines are not needed for low-grade fevers (99 to 101°F) unless your child seems uncomfortable or is not drinking well. Once a child's fever rises above 101.5°F, they generally feel miserable and fever-reducing medicine can help them feel better. Children may also be more likely to drink fluids properly after taking fever-reducing medicines.

Make sure you’re giving your child the correct dose of medicine. Too little medicine won’t be effective, but too much could be dangerous. Follow the instructions on the label carefully and only use the cup or syringe that came with that medicine.

Tip: Never use a household teaspoon. They vary in size, so your dose may be wrong.

Child-safe Fever Medicines

Two types of fever medicine are safe for children: acetaminophen (sold as Tylenol®) and ibuprofen (sold as Motrin® and Advil®). Tylenol is the only fever-reducing medicine approved by the Food and Drug Administration for babies younger than 6 months old.

Motrin has a few advantages over Tylenol for children older than 6 months of age:

• It lasts between six and eight hours.
• It can reduce swelling from teething and ear infections with its anti-inflammatory properties.
• It may be a better choice for children who have asthma or recurrent wheezing.

It’s a good idea to print out the correct dosing for these medicines. Or bookmark these pages from the American Academy of Pediatrics for easy reference:

• Tylenol (acetaminophen) dosing chart
• Motrin and Advil (ibuprofen) dosing chart

When to Take Your Child to See a Doctor

In infants less than 2 months old, a fever is any temperature over 100.4°F. It’s also a concern if your newborn’s temperature is under 96°F. If you find an abnormal temperature in your newborn, call your doctor or go to an urgent care clinic or pediatric emergency care — your newborn needs to be seen right away.

In babies and children older than 3 months, a fever is a temperature greater than 101.5°F. Call your doctor if your child’s temperature reaches 102.2°F or higher.

Most fevers go away in a couple of days. Call your doctor if the fever lasts more than four days or right away if your feverish child has the following symptoms:

• Vomiting or diarrhea
• Earache
• Severe abdominal pain
• Headache
• Stiff neck
• Sore throat
• Trouble breathing
• Pain when urinating
• Swollen joints
• Localized pain
• Purplish or dark rash that does not fade when you press on it
• Refuses to drink fluids

Although fevers can be frightening, they’re a sign of a healthy immune system. If your child has a low fever and no other worrisome symptoms, provide plenty of fluids, rest and love. The fever should go away in a few days.